Picture your bathroom mirror after a hot shower, or a glass of iced tea after it’s been sitting in the warm sun. The steam and dewy drops are evidence of condensation, and they affect your windows more than you may realize.

The simple definition of condensation is when the surface temperature of an object (like your glass of iced tea) is less than the dew point temperature (like the lovely Denver sunshine). Or, you can think of it as the point where warm, moist air meets dryer, cooler air.

So, what does window condensation mean?

Because glass has the lowest temperature of any other surface in your home, you’ll see condensation there first when it meets warmer, moist air. But it isn’t your windows’ fault! In fact, window condensation is just one of the few “cons” of today’s energy efficient designs. You want to keep cold air outside, but that means you’ll also be keeping warm air inside. Now that moisture doesn’t escape as easily, you enjoy the benefits of a less drafty home, but you should also be aware of window condensation that follows.

When does window condensation become a problem?

You shouldn’t see too much window condensation, because it typically only happens during temperature extremes. It only becomes a problem when you see it between the two layers of glass (the thermo-pane). In this case, the hermetic factory seal is broken, is no longer airtight, and will need replacement.

Otherwise, if you fear there may be too much moisture in your home, your windows will likely not be your first warning signal. You’ll see moisture spots on ceilings or walls, paint will peel, and wood will rot or become mildewy. These are all signs of a more serious problem.

How can you prevent window condensation?

You can take a few simple steps to avoid condensation, including cracking an occasional window or door, turning off any humidifying devices or installing a dehumidifier, adding insulated windows, keeping plants in a sunroom, and adding waterproofing protection to basement floors and walls.